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(CNN)The biggest federal inmate release on record will take place this weekend.

About 6,600 inmates will be released, with 16,500 expected to get out the first year. More than 40,000 federal felons could be released early over the next several years, the U.S. Sentencing Commission said.

The sentencing commission decided a year ago to lower maximum sentences for nonviolent drug offenders and to make the change retroactive, with the inmate releases effective November 1, 2015. Sentences were reduced an average of 18%, the commission said.

Early release will be a challenge for the inmates as well as the judicial bureaucracy.

Housing is a problem

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Samuel Hamilton spent 32 years in prison and was let out last year.

"When I was released it was like the stimuli of so many people, just so many people moving at one time and just crossing the street. ... I chose everything with caution," he said.

And even though Hamilton had gotten a master's degree behind bars, it didn't seem to matter when he tried to re-enter the workforce.

"You find yourself not getting the job just because of your criminal history," he said.

But the biggest problem, Hamilton said, was finding a place to live.

"We see so many people coming home without housing," he said.

Most of the inmates will be under supervision, either in halfway houses run by the Bureau of Prisons or by probation officers.

Doug Burris, chief U.S. probation officer for the Eastern District of Missouri, said his district will supervise about 167 inmates and that the influx will be challenging but manageable.

'We have had a full year to prepare'

Two-thirds of those going to the St. Louis area will reside in halfway houses and the rest will go directly into the community.

"We have had a full year to prepare for this," he said. "The U.S. Courts have made it clear that if the workload becomes too strong, that they have supplemental funding. We're optimistic that this is going to work just fine."

Burris said he would like additional funding for drug treatment, job training and more officers. If the inmates break the law, probation officers can petition the court to have inmates' supervision revoked and return them to prison, he said

"We've been down this road twice before," Burris said. "We had two prior crack releases and those went just fine."

Inmates released early don't re-offend at a higher rate than other inmates, the sentencing commission found.

After crack cocaine sentencing guidelines were changed in 2007, a five-year study was conducted. It found 47.8% of crack cocaine inmates who served their full terms re-offended, compared to 43.3% of crack cocaine inmates released early.

Half of released inmates had cocaine offenses

About half the inmates to be released were convicted of crack and powder cocaine offenses, followed by methamphetamine at 31.2%, heroin at 7.4% and marijuana at 8.9%. About 2.7% of the inmates were convicted of Oxycodone offenses and 1% Hydrocodone offenses.

About 25% of those coming out are noncitizens. In a statement to CNN, the U.S. Immigration and Customs Enforcement said it will take 1,700 of those released into custody by next week.

"Seven-hundred sixty-three of these individuals have already been issued final orders of removal, while the others are in varying stages of processing and removal proceedings," ICE said.

Over the next few years, 20,000 Hispanics will be released, along with 14,000 blacks and 11,000 whites.

The state expected to receive the largest number of inmates is Texas, with 2,829, followed by by Florida at 1,200 and Iowa at 785.

Federal judges held re-sentencing hearings across the country during the last year.

Senior U.S. District Judge Jack Weinstein, who presided over thousands of hearings, said he looked at the facts of the criminal's behavior, the inmate's behavior in prison and their family support while assessing whether an offender would be a danger to the community.

"The first question the judge asks himself is, 'If I release this person now or shorten the sentence now, will he be a greater danger to the community?' and the statistics say very clearly no," he said.

'Who's going to watch these people?'

New York City Police Commissioner Bill Bratton said the main problem will be finding adequate staffing to supervise the released inmates. Because of the budget resolution in Congress, the parole department cannot hire more parole officers, he said.

"So who's going to watch these people when they go out on parole?" he said. "And that's effectively what's going on, they're going to be out on parole."

With the commission study concluding that getting out early didn't really matter -- the re-offense rate was about the same -- that leaves the question: Who benefits from early release, the Bureau of Prisons or the prisoners themselves?

The Sentencing Commission said that over time, sentence reductions could result in a savings of up to 79,740 bed years. A bed year, according to the report, is the equivalent of one federal prisoner occupying a prison bed for a year.

The average cost of incarceration for a federal inmate in 2013 was $29,291.25, according to the Federal Register, the daily Journal of the U.S. government.

Based on that average, the total savings to the Bureau of Prisons could be $2.3 billion.